646th Radar Squadron
Emblem of the 646th Radar Squadron
Active	1948 June 1-1966 July 1
Country	United States
Branch	United States Air Force
Type	General Radar Surveillance Squadron assigned to: 1948 June 1 -503d Aircraft Warning Group 1949 December 6 - 503d Aircraft Control and Warning Group 1952 February 6 - 26th Air Division 1953 February 16 - 4709th Defense Wing 1956 October 18 - 4621st Air Defense Wing 1957 January 8 - New York Air Defense Sector 1966 April 1 - 21st Air Division

The 646th Aircraft Control and Warning Squadron was the operational USAF unit of Highlands Air Force Station. The unit operated the Texas Tower 4, an offshore radar annex from 1958 until it collapsed into the Atlantic Ocean on 15 January 1961, killing 28 people. The squadron was activated on 1 June 1948, and renamed to the 646th Radar Squadron (SAGE) on 1 October 1958.

v t e Aerospace Defense Command (ADC)
Bases	CONUS Amarillo Beale Charleston Davis-Monthan Dobbins Dover Dow Duluth Eglin Edwards Ellington Ellsworth England Ent Ethan Allen Fairfax Fallon Fort Gregg-Adams Fort Heath Geiger George Glasgow Grand Forks Grenier Griffiss Gunter Hamilton Hancock Homestead Hurlburt Hunter Imeson Key West Kincheloe Kingsley Kirtland Lackland Laredo Larson Luke MacDill March Malmstrom McCoy McChord McClellan McGhee Tyson McGuire Minneapolis-St. Paul Minot Mitchel New Castle Niagara Falls Norton O'Hare Otis Oxnard Paine Perrin Peterson Pittsburgh Portland Presque Isle R.I. Bong Richards-Gebaur Robins K.I. Sawyer Selfridge Seymour Johnson Sioux City Stead Stewart Suffolk County Tinker Travis Truax Tyndall Vandenberg Vincent Walker Webb Westover Wright-Patterson Wurtsmith Youngstown Overseas Ernest Harmon Frobisher Bay Goose Keflavik McAndrew Pepperrell Thule
Stations	CONUS Adair Aiken Almaden Alpena Antigo Arlington Heights Baker Bedford Bellefontaine Belleville Benton Blaine Brookfield Brunswick Bucks Harbor Burns Calumet Cambria Cape Charles Cape Cod Carmi Caswell Chandler Charleston Cheyenne Mountain Claysburg Clear Colville Condon Continental Divide Cottonwood Cross City Crystal Springs Curlew Custer Cut Bank Dallas Center Dauphin Island Dickinson Duncanville Eldorado Empire Finland Finley Flintstone Fordland Fort Fisher Fort Lee Fortuna Gettysburg Grand Marais Grand Rapids Guthrie Hanna City Havre Highlands Houma Hutchinson Joelton Keno Killeen Kingman Kirksville Klamath Lake Charles Lake City Las Cruces Las Vegas Lewistown Lockport Lufkin Lyndonville Madera Makah Mica Peak Miles City Mill Valley Minot Montauk Moriarty Mount Hebo Mount Laguna Mount Lemmon Naselle North Bend North Charleston North Truro Oklahoma City Olathe Omaha Opheim Osceola Othello Owingsville Ozona Palermo Point Arena Port Austin Port Isabel Pyote Red Bluff Rochester Rockport Rockville (Indiana) Roslyn Rye Saint Albans San Clemente Island Santa Rosa Island Saratoga Springs Sault Ste Marie Shemya Snelling Snow Mountain Sweetwater Texarkana Tierra Amarilla Thomasville Tonopah Topsham Two Creeks Wadena Walnut Ridge Watertown Waverly West Mesa Willow Run Winnemucca Winslow Winston-Salem Woomera Yaak Zapata Overseas Armstrong Baldy Hughes Beausejour Cape Makkovik Cartwright Cut Throat Island Elliston Ridge Fox Harbour Hofn Hopedale Kamloops La Scie Langanes Latrar Melville Puntzi Mountain Ramore Red Cliff Rockville Saglek St. Anthony Saskatoon Mountain Sioux Lookout Spotted Island Stephenville
Air Defense units	Forces Central Air Defense Eastern Air Defense Iceland Western Air Defense First Fourth Tenth Fourteenth Air Divisions 8th 9th 20th 21st 23d 24th 25th 26th 27th 28th 29th 30th 31st 32d 33d 34th 35th 36th 37th 58th 64th 73d 85th Sectors Albuquerque Bangor Boston Chicago Detroit Duluth Goose Grand Forks Great Falls Kansas City Los Angeles Minot Montgomery New York Oklahoma City Phoenix Portland Reno Sault Sainte Marie San Francisco Seattle Sioux City Spokane Stewart Syracuse Washington Wings Fighter 1st 4th 23d 32d 33d 50th 52d 56th 78th 81st 325th 328th 507th Detection and Control 71st 73d 551st 552d Air Defense 46th 4620th 4621st 4622d 4624th 4625th 4627th 4628th 4683d 4700th 4702d 4703d 4704th 4705th 4706th 4707th 4708th 4709th 4710th 4711th 4750th 4751st 4752d 4756th 4780th Groups Fighter 1st 4th 14th 15th 23d 32d 33d 50th 52d 53d 54th 56th 57th 78th 79th 81st 82d 84th 325th 326th 327th 328th 329th 337th 343d 355th 408th 412th 414th 473d 475th 476th 478th 507th Air Defense 10th 500th 501st 502d 503d 514th 515th 516th 517th 518th 519th 520th 521st 525th 527th 528th 529th 530th 533d 534th 564th 566th 567th 568th 575th 637th 665th 678th 692d 701st 751st 762d 765th 778th 780th 827th 858th 4606th 4620th 4676th 4700th 4721st 4722d 4727th 4728th 4729th 4730th 4731st 4732d 4733d 4734th 4735th 4750th 4756th Aircraft Control & Warning 503d 505th 540th 541st 542d 543d 544th 545th 546th 563d 564th 565th 566th Squadrons Aerospace Defense Command Fighter Squadrons Aircraft Control and Warning Squadrons
Major weapon systems	Electronic TB-29 EB-57 EC-121 Fighters Propeller: F-47 F-51 P-61 F-82 Subsonic Jet: P-80 F-84 F-86 F-89 F-94 Supersonic Jet: F-101 F-102 F-104 F-106 Missiles AIM-4 AIM-26 AIR-2 CIM-10 Ships Guardian Interceptor Interdictor Interpreter Investigator Locator Lookout Outpost Pickett Protector Scanner Searcher Skywatcher Tracer Watchman Vigil Texas Towers Texas Tower 2 Texas Tower 3 Texas Tower 4
Miscellaneous	Air Defense Command Emblem Gallery (on Wikimedia Commons) General Surveillance Radar Stations